Single-cell analysis identifies critical regulators of spermatogonial development and differentiation in cattle-yak bulls.

Spermatogenesis is a continuous process in which functional sperm are produced through a series of mitotic and meiotic divisions and morphological changes in germ cells. The aberrant development and fate transitions of spermatogenic cells cause hybrid sterility in mammals. Cattle-yak, a hybrid animal between taurine cattle (Bos taurus) and yak (Bos grunniens), exhibits male-specific sterility due to spermatogenic failure. In the present study, we performed single-cell RNA sequencing analysis to identify differences in testicular cell composition and the developmental trajectory of spermatogenic cells between yak and cattle-yak. The composition and molecular signatures of spermatogonial subtypes were dramatically different between these 2 animals, and the expression of genes associated with stem cell maintenance, cell differentiation and meiotic entry was altered in cattle-yak, indicating the impairment of undifferentiated spermatogonial fate decisions. Cell communication analysis revealed that signaling within different spermatogenic cell subpopulations was weakened, and progenitor spermatogonia were unable or delayed receiving and sending signals for transformation to the next stage in cattle-yak. Simultaneously, the communication between niche cells and germ cells was also abnormal. Collectively, we obtained the expression profiles of transcriptome signatures of different germ cells and testicular somatic cell populations at the single-cell level and identified critical regulators of spermatogonial differentiation and meiosis in yak and sterile cattle-yak. The findings of this study shed light on the genetic mechanisms that lead to hybrid sterility and speciation in bovid species.

Comparative proteomic analysis identifies differentially expressed proteins associated with meiotic arrest in cattle-yak hybrids.

Cattle-yak, the interspecific hybrid between yak and taurine cattle, exhibits male-specific sterility. Massive loss of spermatogenic cells, especially spermatocytes, results in azoospermia in these animals. Currently, the mechanisms underlying meiosis block and defects in spermatocyte development remain elusive. The present study was designed to investigate the differences in the protein composition of spermatocytes isolated from 12-month-old yak and cattle-yak testes. Histological analysis confirmed that spermatocytes were the most advanced germ cells in the testes of yak and cattle-yak at this developmental stage. Comparative proteomic analysis identified a total of 452 differentially abundant proteins (DAPs) in the fluorescence-activated cell sorting (FACS) isolated spermatocytes from cattle-yak and yak. A total of 291 proteins were only present in yak spermatocytes. Gene Ontology analysis revealed that the downregulated DAPs were mostly enriched in the cellular response to DNA damage stimulus and double-strand breaks (DSBs) repair via break-induced replication, while the proteins specific for yak were related to cell division and cycle, spermatogenesis, and negative regulation of the extrinsic apoptotic signaling pathway. Ultimately, these DAPs were related to the critical process for spermatocyte meiotic events, including DSBs, homologous recombination, synapsis, crossover formation, and germ cell apoptosis. The database composed of proteins associated with spermatogenesis, including KPNA2, HTATSF1, TRIP12, STIP1, LZTFL1, LARP7, MTCH2, STK31, ROMO1, CDK5AP2, DNMT1, RBM44, and CHRAC1, is the focus of further research on male hybrid sterility. In total, these results provide insight into the molecular mechanisms underlying failed meiotic processes and male infertility in cattle-yak.

Transcriptome analysis reveals dysregulated gene expression networks in Sertoli cells of cattle-yak hybrids.

Cattle-yak, the hybrid offspring of yak and taurine cattle, exhibits male sterility with normal female fertility. Spermatogenesis is arrested in adult cattle-yak, and apoptosis is elevated in spermatogenic cells. Currently, the mechanisms underlying these defects remain elusive. Sertoli cells are the only somatic cells that directly interact with spermatogenic cells in the seminiferous tubules and play essential roles in spermatogenesis. The present study was designed to investigate gene expression signatures and potential roles of Sertoli cells in hybrid sterility in cattle-yak. Immunohistochemical analysis showed that the 5 mC and 5hmC signals in Sertoli cells of cattle-yaks were significantly different from those of age-matched yaks (P < 0.05). Transcriptome profiling of isolated Sertoli cells identified 402 differentially expressed genes (DEGs) between cattle-yaks and yaks. Notably, niche factor glial cell derived neurotrophic factor (GDNF) was upregulated, and genes involved in retinoic acid (RA) biogenesis were changed in Sertoli cells of cattle-yak, suggesting possible impairments of spermatogonial fate decisions. Further studies showed that the numbers of proliferative gonocytes and undifferentiated spermatogonia in cattle-yak were significantly higher than those in yak (P < 0.01). Exogenous GDNF significantly promoted the proliferation of UCHL1-positive spermatogonia in yaks. Therefore, we concluded that altered GDNF expression and RA signaling impacted the fate decisions of undifferentiated spermatogonia in cattle-yak. Together, these findings highlight the role of Sertoli cells and their derived factors in hybrid sterility.

Aspirin triggers ferroptosis in hepatocellular carcinoma cells through restricting NF-κB p65-activated SLC7A11 transcription.

A number of studies have shown that aspirin, as commonly prescribed drug, prevents the development of hepatocellular carcinoma (HCC). Ferroptosis as a dynamic tumor suppressor plays a vital role in hepatocarcinogenesis. In this study we investigated whether aspirin affected ferroptosis in liver cancer cells. RNA-seq analysis revealed that aspirin up-regulated 4 ferroptosis-related drivers and down-regulated 5 ferroptosis-related suppressors in aspirin-treated HepG2 cells. Treatment with aspirin (4 mM) induced remarkable ferroptosis in HepG2 and Huh7 cells, which was enhanced by the ferroptosis inducer erastin (10 µM). We demonstrated that NF-κB p65 restricted ferroptosis in HepG2 and Huh7 cells through directly binding to the core region of SLC7A11 promoter and activating the transcription of ferroptosis inhibitor SLC7A11, whereas aspirin induced ferroptosis through inhibiting NF-κB p65-activated SLC7A11 transcription. Overexpression of p65 rescued HepG2 and Huh7 cells from aspirin-induced ferroptosis. HCC patients with high expression levels of SLC7A11 and p65 presented lower survival rate. Functionally, NF-κB p65 blocked the aspirin-induced ferroptosis in vitro and in vivo, which was attenuated by erastin. We conclude that aspirin triggers ferroptosis by restricting NF-κB-activated SLC7A11 transcription to suppress the growth of HCC. These results provide a new insight into the mechanism by which aspirin regulates ferroptosis in hepatocarcinogenesis. A combination of aspirin and ferroptosis inducer may provide a potential strategy for the treatment of HCC in clinic.

Cognitive function and its influencing factors in empty-nest elderly and non-empty-nest elderly adults in China.

INTRODUCTION: We investigated cognitive function and its influencing factors in empty-nest and non-empty-nest elderly adults in China. RESULTS: Cognitive function was better in empty-nest elderly living as a couple but worse in those living alone than in non-empty-nest elderly. Older age, rural habitation, poorer instrumental activities of daily living, and depression were risk factors for cognitive decline, while higher education was protective. Women had poorer cognitive function than men among non-empty-nest elderly and empty-nest elderly living as a couple. Among non-empty-nest elderly, those who were divorced/widowed/never married, underweight or economically active exhibited poorer cognitive function. Having two or more chronic diseases and being overweight were associated with better cognitive function among empty-nest elderly living as a couple. CONCLUSION: These findings suggest that cognitive function is poorest in empty-nest elderly living alone and best in empty-nest elderly living as a couple. The factors influencing cognitive function differed according to empty-nest status, which should be considered in interventions. METHODS: 5549 elderly from the 2015 China Health and Retirement Longitudinal Study were included in this study. Cognitive function was evaluated using the Telephone Interview for Cognitive Status, episodic memory tests and visuospatial ability assessments. Factors influencing cognitive function were determined via multiple linear regression analysis.

WTAP Function in Sertoli Cells Is Essential for Sustaining the Spermatogonial Stem Cell Niche.

Sertoli cells are the major component of the spermatogonial stem cell (SSC) niche; however, regulatory mechanisms in Sertoli cells that dictate SSC fate decisions remain largely unknown. Here we revealed features of the N6-methyladenosine (m6A) mRNA modification in Sertoli cells and demonstrated the functions of WTAP, the key subunit of the m6A methyltransferase complex in spermatogenesis. m6A-sequencing analysis identified 21,909 m6A sites from 15,365 putative m6A-enriched transcripts within 6,122 genes, including many Sertoli cell-specific genes. Conditional deletion of Wtap in Sertoli cells resulted in sterility and the progressive loss of the SSC population. RNA sequencing and ribosome nascent-chain complex-bound mRNA sequencing analyses suggested that alternative splicing events of transcripts encoding SSC niche factors were sharply altered and translation of these transcripts were severely dysregulated by Wtap deletion. Collectively, this study uncovers a novel regulatory mechanism of the SSC niche and provide insights into molecular interactions between stem cells and their cognate niches in mammals.

The expression of histone methyltransferases and distribution of selected histone methylations in testes of yak and cattle-yak hybrid.

Interspecies hybridization exists widely in nature and plays an important role in animal evolution and adaptation. It is commonly recognized that male offspring of interspecies hybrid are often sterile, which presents a crucial way of reproductive isolation. Currently, the mechanisms underlying interspecies hybrid male sterility are not well understood. Cattle-yak, progeny of yak (Bos grunniens) and cattle (Bos taurus) cross, is a unique animal model for investigating hybrid male sterility. Because histone modifications are vital for spermatogenesis, herein, we examined expressions of histone methyltransferases (HMTs) and distributions of histone methylations in the yak and cattle-yak testis. Histological examination of seminiferous tubules revealed that gonocytes and spermatocytes were established normally, however, spermatogenesis was arrested at the meiosis phase began at 10 months after birth in the hybrids. SUV420H1 was the only HMT examined showing a significant enrichment in cattle-yak testes at 3 months. Relative expressions of MLL5, SETDB1 and SUV420H1 were increased while SETDB2 and EZH2 were decreased in cattle-yak testes at 10 months. Relative concentrations of MLL5 and SUV420H1 were again increased while EHMT2 and PRDM9 expressions were decreased at 24 months. Immunofluorescent detection of selected histone methylations in cross-sections of testicular tissues or meiotic chromosomes demonstrated that depletion of H3K4me3 and significant enrichment of H3K27me3 and H4K20me3 were observed in Sertoli cells of cattle-yak. Levels and localizations of H3K4me3, H3K9me1, H3K9me3 and H4K20me3 were strikingly different in meiotic chromosomes of cattle-yak spermatocytes. These results highlighted the potential roles of histone methylations in spermatogenic failure and hybrid male sterility.

Comparison between thoracoscopic and open approaches in thymoma resection.

BACKGROUND: To investigate the feasibility and indications of video-assisted thoracic surgery (VATS) in thymoma resection. METHODS: The clinical data of 103 patients undergoing thymoma resection via different approaches [including conventional lateral thoracotomy approach (LTA) in 41 cases, median sternotomy approach (MSA) in 40 cases, and right-sided VATS in 22 cases] were analyzed. Among them, 59, 13, 25, and 6 patients were in Masaoka stage I, II, III, and IV, respectively. Myasthenia gravis (MG) was also found in 54 cases. The patients were followed up for postoperative survival and the improvement in MG. The prognostic indicators of patients undergoing thymoma resection via different surgical approaches (i.e., LTA, MSA, and VATS) were statistically analyzed. RESULTS: Eight of 103 patients died. Six patients underwent unilateral sacral nerve resection, among whom 4 patients developed respiratory dysfunction, and 3 died. Two patients died of MG after surgery, 1 patient died of tumor recurrence and metastasis, 1 patient died of heart disease, and the cause of death was unknown in the remaining patient. The drainage time was shorter in VATS group than in open groups, along with smaller tumor size. The VATS group also had shorter hospital stay in the whole series and the subgroup without accompanying MG. The improvement in MG showed no significant difference among the three surgical groups. Both 5- and 10-year survival rates were 91% in the entire cohort. CONCLUSIONS: VATS is like a conventional surgeries for improving MG in thymoma patients with accompanying MG. VATS resection can still be considered for thymoma that only invades the mediastinal pleura. For thymomas that have intact capsules and have not invaded mediastinal pleura, MSA surgery shall be performed to ensure patient safety if the anteroposterior diameters of the tumors are large and the masses have produced severe compression of the innominate vein, even if the tumors are still in the Masaoka stage II. For thymomas with large left-to-right diameters and with most parts of the tumors located in the left thoracic cavity, a left-sided approach (either VATS or an open approach) may be used in the absence of MG; if MG accompanies the condition, an MT approach or a bilateral VATS may be considered. In patients with unilateral pericardial phrenic nerve and/or local pericardial involvement, right-sided VATS thymectomy may be considered for thymomas located at the right side and bilateral VATS surgery can be performed for tumors located at the left side. In summary, VATS is feasible for the treatment of thymoma complicated by MG. VATS can be performed in patients with Masaoka stage I, II and (a certain portion of) III thymoma; for some patients with Masaoka stage II thymoma, especially those with compression of the innominate vein, the use of VATS should be cautious.

Effect of combined treatment including surgery and postoperative adjuvant therapy on spinal metastases of Tomita type 7.

OBJECTIVES: Identify the efficacy of multidisciplinary treatment including palliative spinal surgery on patients with Tomita type 7 spinal metastases. PATIENTS AND METHODS: A retrospective analysis of surgery treated spinal metastatic patients from January 2013 to December 2016 in Tianjin Medical University Cancer Institute and Hospital were performed. Surgical procedures and intraoperative parameters and postoperative adjuvent treatments were studied. Patients' demographic characteristics and medical conditions including paralysis statues, quality of life and pain levels and postoperative survival time were identified. RESULTS: 50 patients were identified with mean age at the time of surgery of 57.68 years old (range 27-78 years). The mean Tokuhashi score was 8.48 and the spinal instability neoplastic score (SINS) averaged at 10.52 points. 48 patients (96%) encountered epidural spinal cord compression. Kaplan-Meier method determined median postoperative survival time was 12.00 months (95% CI: 7.05-16.95 months). The mean score of visual analogue scale (VAS) decreased from 7.66 preoperatively to 1.96 postoperatively. The Frankel scale was improved by at least one grade in 47 patients. Patient's quality of life showed significant improvements. CONCLUSION: Multidisciplinary treatment including palliative spinal surgery was associated with alleviating pain, improving neurologic function and quality of life in patients with Tomita type 7 spinal metastases.

Novel anti-melanoma treatment: focus on immunotherapy.

Melanoma is an intractable cancer that is aggressive, lethal, and metastatic. The prognosis of advanced melanoma is very poor because it is insensitive to chemotherapy and radiotherapy. The incidence of melanoma has been ascending stably for years worldwide, accompanied by increasing mortality. New approaches to managing this deadly disease are much anticipated to enhance the cure rate and to extend clinical benefits to patients with metastatic melanoma. Due to its high degree of immunogenicity, melanoma could be a good target for immunotherapy, which has been developed for decades and has achieved certain progress. This article provides an overview of immunotherapy for melanoma.

The prognostic role of PRUNE2 in leiomyosarcoma.

PRUNE2 plays an important role in regulating tumor cell differentiation, proliferation, and invasiveness in neuroblastoma. Our previous study revealed that PRUNE2/OBSCN two-gene relative expression classifer accurately differentiated leiomyosarcoma from gastrointestinal stromal tumor. However, the association between PRUNE2 expression and prognosis in leiomyosarcoma is poorly understood. In this study, we evaluated the prognostic role of PRUNE2 in leiomyosarcoma. PRUNE2 expression was detected using immunohistochemistry in 30 formalin-fixed, paraffin-embedded leiomyosarcoma tissues from MD Anderson Cancer Center, and high expression was detected in 36.7% (11/30) of the samples. To validate these results, immunohistochemistry was performed on another cohort of 45 formalin-fixed, paraffin-embedded leiomyosarcoma tissues from Tianjin Medical University Cancer Institute & Hospital, and high PRUNE2 protein expression was detected in 37.8% (17/45) of the samples. Moreover, elevated PRUNE2 expression was significantly associated with tumor size (P = 0.03) and hemorrhage/cyst (P = 0.014), and was an independent favorable prognostic factor for overall survival in leiomyosarcoma patients from Tianjin Medical University Cancer Institute & Hospital (P < 0.05). These data suggest that increased PRUNE2 protein expression may serve as a favorable prognostic marker in human leiomyosarcoma.

Quercetin inhibits human breast cancer cell proliferation and induces apoptosis via Bcl-2 and Bax regulation.

Breast cancer is a disease in which cancer cells form in the tissues of the breast. The present study aimed to explore the effect of the flavonoid compound quercetin on the growth and apoptosis of human breast cancer cells. Varying concentrations (12.5, 25, 50, 100, 200 µM) of quercetin were applied to cultured MCF-7 human breast cancer cells for defined lengths of time. At 50 to 200 µM doses, quercetin significantly inhibited the proliferation of MCF-7 cells assessed by MTT colorimetry, in both dose- and time-dependent manners (P<0.05). The compound also increased apoptosis after 48 h of exposure (P<0.05). Furthermore, following quercetin treatment Bcl-2 expression decreased significantly while Bax expression increased significantly (P<0.05). In brief, quercetin inhibits cell growth and induces apoptosis in MCF-7 human breast cancer cells. The mechanisms behind these effects may stem from the downregulation of Bcl-2 protein expression and upregulation of Bax expression.

[Lethal effects of nanoliposome encapsulated cisplatin on Saos-2 cells and its distribution in nude mice bearing human].

OBJECTIVE: To investigate the killing effect of nanoliposome encapsulated cisplatin (NLE-CDDP) on human osteosarcoma cell line Saos-2 and explore the distribution of platinum (Pt) in tumor-bearing mice. METHODS: Saos-2 cells were cultured at different concentrations of NLE-CDDP. MTT assay, inverted microscopic observation and flow cytometry assay(FCM)were used to observe the antiproliferative effect of NLE-CDDP on the human osteosarcoma cells. Antitumor effect of NLE-CDDP was determined using the xenografts models of human osteosarcoma cell Saos-2 in nude mice. The Pt concentration in the tissues of tumor-transplanted mice was determined by atomic spectrophotometer. RESULTS: When treated at different concentrations of NLE-CDDP for 24-96 hours, the survival rate of Saos-2 cells decreased significantly(P<0.05). At the same time point, the inhibitory effect of NLE-CDDP was stronger than that of CDDP;Degeneration and necrosis of Saos-2 cells increased; the apoptosis increased and the S phase reduced. This study demonstrated that NLE-CDDP had obvious anti-tumor activity. Within 1 hour of injection, in NLE-CDDP group plasma platinum concentration was 4.4-fold that in CDDP group; 2 hours later, platinum was not detected in the blood of CDDP group; 24 hours later, platinum still could be detected in NLE-CDDP group at 2.76 mumol/L. During the first hour after injection of NLE-CDDP, the platinum content of the kidney was 50% less than that of CDDP group. Platinum in NLE-CDDP group showed rapid higher accumulation in the liver, spleen and tumor compared with CDDP group, and within 24 hours platinum reached the peak concentration in the spleen. CONCLUSION: The antitumor efficacy of NLE-CDDP on Saos-2 tumor is higher than that CDDP alone, and its mechanism is delaying rapid clearance from circulation.