L(1)10Bb serves as a conservative determinant for soma-germline communications via cellular non-autonomous effects within the testicular stem cell niche.

The testicular stem cell niche is the central regulator of spermatogenesis in Drosophila melanogaster. However, the underlying regulatory mechanisms are unclear. This study demonstrated the crucial role of lethal (1) 10Bb [l(1)10Bb] in regulating the testicular stem cell niche. Dysfunction of l(1)10Bb in early-stage cyst cells led to male fertility disorders and compromised cyst stem cell maintenance. Moreover, the dysfunction of l(1)10Bb in early-stage cyst cells exerted non-autonomous effects on germline stem cell differentiation, independently of hub signals. Notably, our study highlights the rescue of testicular defects through ectopic expression of L(1)10Bb and the human homologous protein BUD31 homolog (BUD31). In addition, l(1)10Bb dysfunction in early-stage cyst cells downregulated the expression of spliceosome subunits in the Sm and the precursor RNA processing complexes. Collectively, our findings established l(1)10Bb as a pivotal factor in the modulation of Drosophila soma-germline communications within the testicular stem cell niche.

Single-cell RNA-sequencing reveals the transcriptional landscape of ND-42 mediated spermatid elongation via mitochondrial derivative maintenance in Drosophila testes.

During spermatogenesis, mitochondria extend along the whole length of spermatid tail and offer a structural platform for microtubule reorganization and synchronized spermatid individualization, that eventually helps to generate mature sperm in Drosophila. However, the regulatory mechanism of spermatid mitochondria during elongation remains largely unknown. Herein, we demonstrated that NADH dehydrogenase (ubiquinone) 42 kDa subunit (ND-42) was essential for male fertility and spermatid elongation in Drosophila. Moreover, ND-42 depletion led to mitochondrial disorders in Drosophila testes. Based on single-cell RNA-sequencing (scRNA-seq), we identified 15 distinct cell clusters, including several unanticipated transitional subpopulations or differentiative stages for testicular germ cell complexity in Drosophila testes. Enrichments of the transcriptional regulatory network in the late-stage cell populations revealed key roles of ND-42 in mitochondria and its related biological processes during spermatid elongation. Notably, we demonstrated that ND-42 depletion led to maintenance defects of the major mitochondrial derivative and the minor mitochondrial derivative by affecting mitochondrial membrane potential and mitochondrial-encoded genes. Our study proposes a novel regulatory mechanism of ND-42 for spermatid mitochondrial derivative maintenance, contributing to a better understanding of spermatid elongation.

Single-cell RNA sequencing reveals cell landscape following antimony exposure during spermatogenesis in Drosophila testes.

Antimony (Sb), is thought to induce testicular toxicity, although this remains controversial. This study investigated the effects of Sb exposure during spermatogenesis in the Drosophila testis and the underlying transcriptional regulatory mechanism at single-cell resolution. Firstly, we found that flies exposed to Sb for 10 days led to dose-dependent reproductive toxicity during spermatogenesis. Protein expression and RNA levels were measured by immunofluorescence and quantitative real-time PCR (qRT-PCR). Single-cell RNA sequencing (scRNA-seq) was performed to characterize testicular cell composition and identify the transcriptional regulatory network after Sb exposure in Drosophila testes. scRNA-seq analysis revealed that Sb exposure influenced various testicular cell populations, especially in GSCs_to_Early_Spermatogonia and Spermatids clusters. Importantly, carbon metabolism was involved in GSCs/early spermatogonia maintenance and positively related with SCP-Containing Proteins, S-LAPs, and Mst84D signatures. Moreover, Seminal Fluid Proteins, Mst57D, and Serpin signatures were highly positively correlated with spermatid maturation. Pseudotime trajectory analysis revealed three novel states for the complexity of germ cell differentiation, and many novel genes (e.g., Dup98B) were found to be expressed in state-biased manners during spermatogenesis. Collectively, this study indicates that Sb exposure negatively impacts GSC maintenance and spermatid elongation, damaging spermatogenesis homeostasis via multiple signatures in Drosophila testes and therefore supporting Sb-mediated testicular toxicity.

Tumor budding as an indicator for lymph node metastasis and prognosis of early gastric cancer.

BACKGROUND: Tumor budding, considered as an independent risk factor reflecting prognosis of some malignant tumors, has been recognized as an important clinicopathological indicator of colorectal carcinoma. However, the evaluation of tumor budding and its clinicopathological significance in gastric cancer remain controversial. AIM: To investigate the relationship between tumor budding and clinical biological behavior of early gastric cancer (EGC) and assess the predictive value of tumor budding for lymph node metastasis as well as its impact on prognosis of EGC patients. METHODS: Tissue specimens of 164 EGC patients who underwent radical gastrectomy between June 2011 and January 2017 from a single center were selected to carry out HE and CK staining respectively, so as to evaluate tumor budding under light microscopy. Clinicopathological data and follow-up results of all EGC patients were collected for statistical analysis among tumor budding, EGC clinicopathological factors and prognosis. RESULTS: Of all 164 EGC patients, there were 84 (51.2%) cases with mucosal invasion and 80 (48.8%) cases with submucosal invasion. Meanwhile, 32 cases (19.5%) had lymph node metastasis, 19 (11.6%) had lympho-vascular invasion and 4 (2.4%) had early recurrence. Tumor budding were observed in 90 (54.9%) patients, with low-grade budding 68 (41.5%) cases and high-grade budding 22 (13.4%) cases. Tumor budding was closely correlated with tumor size (c2 = 6.609, P = 0.037), tumor histologic differentiation (c2 = 10.522, P = 0.032), depth of invasion (c2 = 8.787, P = 0.012), lymph node metastasis (c2 = 24.226, P < 0.01), TNM stage (c2 = 24.226, P < 0.01), lympho-vascular invasion (c2 = 8.225, P = 0.016) and early recurrence (c2 = 6.462, P = 0.040). Additionally, tumor budding was correlated with postoperative survival rate as well. Multiple regression analysis revealed that tumor budding was an independent influencing factor of postoperative 3-year survival rate, 5-year survival rate, OS, DFS and DSS (P < 0.05). Furthermore, tumor budding was an independent risk factor of lymph node metastasis of EGC patients, and high-grade budding was a high-risk indicator of lymph node metastasis. CONCLUSION: Tumor budding is related to tumor size, tumor histologic differentiation, depth of invasion, lymph node metastasis, lympho-vascular invasion and early recurrence of EGC. Tumor budding, especially high-grade budding can serve as an indicator for predicting lymph node metastasis of EGC, and high-grade budding could be an important parameter for evaluating prognosis of EGC patients.

Highly pathogenic coronavirus N protein aggravates inflammation by MASP-2-mediated lectin complement pathway overactivation.

Excessive inflammatory responses contribute to the pathogenesis and lethality of highly pathogenic human coronaviruses, but the underlying mechanism remains unclear. In this study, the N proteins of highly pathogenic human coronaviruses, including severe acute respiratory syndrome coronavirus (SARS-CoV), middle east respiratory syndrome coronavirus (MERS-CoV) and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), were found to bind MASP-2, a key serine protease in the lectin pathway of complement activation, resulting in excessive complement activation by potentiating MBL-dependent MASP-2 activation, and the deposition of MASP-2, C4b, activated C3 and C5b-9. Aggravated inflammatory lung injury was observed in mice infected with adenovirus expressing the N protein. Complement hyperactivation was also observed in SARS-CoV-2-infected patients. Either blocking the N protein:MASP-2 interaction, MASP-2 depletion or suppressing complement activation can significantly alleviate N protein-induced complement hyperactivation and lung injury in vitro and in vivo. Altogether, these data suggested that complement suppression may represent a novel therapeutic approach for pneumonia induced by these highly pathogenic coronaviruses.

Individual behavioral and sporting risk factors affecting injuries in recreational skiers and snowboarders: a case-control study.

This case-control study aimed to analysis of the relationship between individual behaviours and sports risk factors and injuries among skiers and snowboarders. During the 2021-2022 winter season, 1132 injured and 1069 non-injured skiers and snowboarders were surveyed regarding demographic, self-reported individual behavioural and sporting characteristics. Multivariate regression analysis revealed previous snow-sports injury (OR: 26.39, 95% CI: 13.32-52.31, P < 0.001), nervousness (OR: 3.78, 95% CI: 2.91-4.90, P < 0.001), calm (OR: 1.90, 95% CI: 1.46-2.48, P < 0.001) and fearful (OR: 20.60, 95% CI: 11.45-37.04, P < 0.001) emotional states, and higher risk-taking behaviours (OR: 3.72, 95% CI: 2.87-4.83, P < 0.001) were important risk factors associated with injuries to all skiers and snowboarders. Compared to snowboarders, the risk of injury to skiers was more likely to increase as the length of their skiing experience increases. Emotional and cognitive levels appear to be important conditions that influence injuries to skiers and snowboarders, a proper understanding of the potential interactions between cognition and behaviour appears to be important for public ski safety management.

Cyst stem cell lineage eIF5 non-autonomously prevents testicular germ cell tumor formation via eIF1A/eIF2γ-mediated pre-initiation complex.

BACKGROUND: Stem cell niche maintains stem cell population identity and is essential for the homeostasis of self-renewal and differentiation in Drosophila testes. However, the mechanisms of CySC lineage signals-mediated soma-germline communications in response to external stimuli are unclear. METHODS: Pre-initiation complex functions were evaluated by UAS-Gal4-mediated cell effects. RNA sequencing was conducted in NC and eIF5 siRNA-treated cells. Genetic interaction analysis was used to indicate the relationships between eIF5 and eIF1A/eIF2γ in Drosophila testes. RESULTS: Here, we demonstrated that in CySCs, translation initiation factor eIF5 mediates cyst cell differentiation and the non-autonomously affected germ cell differentiation process. CySCs lacking eIF5 displayed unbalanced cell proliferation and apoptosis, forming testicular germ cell tumors (TGCTs) during spermatogenesis. eIF5 transcriptional regulation network analysis identified multiple metabolic processes and several key factors that might be involved in germ cell differentiation and TGCT formation. Importantly, knockdown of eIF1A and eIF2γ, key components of pre-initiation complex, mimicked the phenotype of knocking down eIF5 in the stem cell niche of Drosophila testes. Genetic interaction analysis indicated that eIF5 was sufficient to rescue the phenotype of tumorlike structures induced by down-regulating eIF1A or eIF2γ in CySCs. CONCLUSIONS: These findings demonstrated that CySC lineage eIF5, together with eIF1A or eIF2γ, mediates soma-germline communications for the stem cell niche homeostasis in Drosophila testes, providing new insights for the prevention of TGCTs.

BMI1 promotes spermatogonial stem cell maintenance by epigenetically repressing Wnt10b/ß-catenin signaling.

The self-renewal of spermatogonial stem cells (SSCs) requires a special microenvironment and is strictly controlled. Previously, we identified BMI1 as a key regulator of spermatogenesis in a knock-out mouse model. However, the mechanisms by which BMI1 regulates SSC maintenance remain largely unknown. Herein, we show that BMI1 is essential for SSC maintenance. BMI1 directs the transcriptional repression of target genes by increasing H2AK119ub and reducing H3K4me3 in SSCs. Furthermore, BMI1 inhibition resulted in the transcriptional activation of Wnt10b and thereby promoted the nuclear translocation of ß-catenin in SSCs. Importantly, the suppression of Wnt/ß-catenin signaling restored both the cytoplasmic expression of ß-catenin and SSC maintenance in BMI1-deficient SSCs. Finally, we demonstrated that Wnt/ß-catenin signaling was also involved in BMI1-mediated SSC maintenance in vivo. Altogether, our study not only reveals a novel mechanism for BMI1 in the process of SSC maintenance, but also provides a potential new strategy for treating male infertility.

The MERS-CoV N Protein Regulates Host Cytokinesis and Protein Translation via Interaction With EF1A.

Middle East respiratory syndrome coronavirus (MERS-CoV), a pathogen causing severe respiratory disease in humans that emerged in June 2012, is a novel beta coronavirus similar to severe acute respiratory syndrome coronavirus (SARS-CoV). In this study, immunoprecipitation and proximity ligation assays revealed that the nucleocapsid (N) protein of MERS-CoV interacted with human translation elongation factor 1A (EF1A), an essential component of the translation system with important roles in protein translation, cytokinesis, and filamentous actin (F-actin) bundling. The C-terminal motif (residues 359-363) of the N protein was the crucial domain involved in this interaction. The interaction between the MERS-CoV N protein and EF1A resulted in cytokinesis inhibition due to the formation of inactive F-actin bundles, as observed in an in vitro actin polymerization assay and in MERS-CoV-infected cells. Furthermore, the translation of a CoV-like reporter mRNA carrying the MERS-CoV 5'UTR was significantly potentiated by the N protein, indicating that a similar process may contribute to EF1A-associated viral protein translation. This study highlights the crucial role of EF1A in MERS-CoV infection and provides new insights into the pathogenesis of coronavirus infections.

CG6015 controls spermatogonia transit-amplifying divisions by epidermal growth factor receptor signaling in Drosophila testes.

Spermatogonia transit-amplifying (TA) divisions are crucial for the differentiation of germline stem cell daughters. However, the underlying mechanism is largely unknown. In the present study, we demonstrated that CG6015 was essential for spermatogonia TA-divisions and elongated spermatozoon development in Drosophila melanogaster. Spermatogonia deficient in CG6015 inhibited germline differentiation leading to the accumulation of undifferentiated cell populations. Transcriptome profiling using RNA sequencing indicated that CG6015 was involved in spermatogenesis, spermatid differentiation, and metabolic processes. Gene Set Enrichment Analysis (GSEA) revealed the relationship between CG6015 and the epidermal growth factor receptor (EGFR) signaling pathway. Unexpectedly, we discovered that phosphorylated extracellular regulated kinase (dpERK) signals were activated in germline stem cell (GSC)-like cells after reduction of CG6015 in spermatogonia. Moreover, Downstream of raf1 (Dsor1), a key downstream target of EGFR, mimicked the phenotype of CG6015, and germline dpERK signals were activated in spermatogonia of Dsor1 RNAi testes. Together, these findings revealed a potential regulatory mechanism of CG6015 via EGFR signaling during spermatogonia TA-divisions in Drosophila testes.

Early diagnostic potential of APC hypermethylation in esophageal cancer.

BACKGROUND: The hypermethylation of APC gene is observed in various cancers, including esophageal cancer (EC). However, the association between APC methylation and the initiation and progression of EC is poorly understood. PURPOSE AND METHODS: The current study systematically reviewed studies on abnormal methylation of APC in EC and quantitatively synthesized 18 studies by meta-analysis involving 1008 ECs, 570 Barrett's esophagus (BE), and 782 controls. RESULTS: Our results showed higher methylation of APC in EC (OR = 23.33, P < 0.001) and BE (OR = 9.34, P < 0.001) than in normal controls. Whereas APC methylation in EC was similar to that in BE (P = 0.052), it was not associated with tumor stage (P = 0.204). Additionally, APC methylation was not significantly associated with overall survival (OS) and relapse-free survival (RFS) in patients with EC. The performance of APC methylation for the detection of EC and BE achieved areas under the receiver operating characteristic curves of 0.94 and 0.88, respectively. CONCLUSION: Our results imply that APC methylation detection is a potential diagnostic biomarker for EC and BE.

Hydrogen bonds and steric effects induced structural modulation of three layered iodoplumbate hybrids from nonperovskite to perovskite structure.

Directed by diprotonated organic diamines containing both primary and tertiary ammonium groups, three layered iodoplumbate hybrids, {[H2DMPDA][PbI4]}n (1), {[H2DEPDA]4[Pb5I18]}n (2) and {[H2TMEDA][Pb3I8]}n (3) (DMPDA = N,N-dimethyl-1,3-propanediamine, DEPDA = N,N-diethyl-1,3-propanediamine, TMEDA = N,N,N',N'-tetramethylethylenediamine), have been synthesized solvothermally. 1 presents a layered perovskite structure based on corner-sharing PbI6 octahedra, compound 2 consists of a Pb4I20 perovskite motif and a Pb2I10 dimeric motif and compound 3 comprises Pb3I13 units connected by face-sharing and edge-sharing modes. Structural modulations from nonperovskite to perovskite structure are strongly correlated to steric effects and hydrogen bonding interaction at the organic-inorganic interface. Band gaps for 1-3 , estimated as 2.21, 2.58 and 2.73 eV, respectively, also reveal an interesting correlation with structural modulation, and the red shift for 1 is attributed to large Pb-I(equatorial)-Pb bond angles.