E3 ligase Cul2 mediates Drosophila early germ cell differentiation through targeting Bam

Polyphyllin I Inhibits the Metastasis of Cervical Cancer Through the Regulation of the β-Catenin Signaling Pathway

Cervical cancer ranks as the fourth most prevalent cancer and cause of cancer-related mortality among women globally. It exhibits a recurrence/metastasis rate of approximately 30% and a dismal 5-year survival of only 17% in metastatic cases. Despite significant advancements in surgical techniques, chemoradiotherapy, and targeted therapies, effective treatment options for metastatic cervical cancer remain limited. This study explored Polyphyllin I (PPI), which is a monomeric compound derived from the Rhizoma of Paris Polyphyllin, as a potential inhibitor of cervical cancer metastasis. Mechanistically, PPI directly interacted with β-catenin at the Ser552 site, inhibiting its phosphorylation and subsequent nuclear translocation, thereby suppressing TCF/LEF transcriptional activity and downstream EMT transcription factors (ZEB1, Slug, Snail, and Twist). Notably, PPI promoted β-catenin degradation via the autophagy-lysosomal pathway, as confirmed by CHX chase assays and the detection of the p62 and LC3 proteins, without altering the mRNA levels of β-catenin. In vitro experiments demonstrated that PPI effectively suppressed the migration and invasion of HO-8910PM cells by reversing the process of EMT. Additionally, PPI effectively inhibited TCF/LEF signaling, leading to a reduction in the transcription levels of EMT-associated transcription factors (EMT-TFs), which was mediated by the TCF/LEF family downstream of β-catenin. Furthermore, PPI exhibited inhibitory effects on proliferation, migration, and invasion in both HPV-positive (SiHa) and HPV-negative (C33A) cervical cancer cells. In vivo, PPI significantly suppressed peritoneal metastasis in a luciferase-labeled HO-8910PM xenograft mouse model. These findings reveal the dual role of PPI in blocking β-catenin signaling and inducing β-catenin depletion, thereby effectively restraining metastatic progression. This study underscores the potential of PPI as a promising therapeutic candidate for targeting cervical cancer metastasis through autophagy-mediated β-catenin regulation, offering a novel strategy to address current treatment limitations.

Wolbachia pipientis modulates germline stem cells and gene expression associated with ubiquitination and histone lysine trimethylation to rescue fertility defects in Drosophila

Wolbachia pipientis are maternally transmitted endosymbiotic bacteria commonly found in arthropods and nematodes. These bacteria manipulate reproduction of the host to increase their transmission using mechanisms, such as cytoplasmic incompatibility, that favor infected female offspring. The underlying mechanisms of reproductive manipulation by W. pipientis remain unresolved. Interestingly, W. pipientis infection partially rescues female fertility in flies containing hypomorphic mutations of bag of marbles (bam) in Drosophila melanogaster, which plays a key role in germline stem cell daughter differentiation. Using RNA-seq, we find that W. pipientis infection in bam hypomorphic females results in differential expression of many of bam's genetic and physical interactors and enrichment of ubiquitination and histone lysine methylation genes. We find that W. pipientis also rescues the fertility and germline stem cell functions of a subset of these genes when knocked down with RNAi in a wild-type bam genotype. Our results show that W. pipientis interacts with ubiquitination and histone lysine methylation genes which could be integral to the mechanism by which W. pipientis modulates germline stem cell gene function.

Cul2 Is Essential for the Drosophila IMD Signaling-Mediated Antimicrobial Immune Defense

Cullin 2 (Cul2), a core component of the Cullin-RING E3 ubiquitin ligase complex, is integral to regulating distinct biological processes. However, its role in innate immune defenses remains poorly understood. In this study, we investigated the functional significance of Cul2 in the immune deficiency (IMD) signaling-mediated antimicrobial immune reactions in Drosophila melanogaster (fruit fly). We demonstrated that loss-of-function of Cul2 led to a marked reduction in antimicrobial peptide induction following bacterial infection, which was associated with increased fly mortality and bacterial load. The proteomic analysis further revealed that loss-of-function of Cul2 reduced the expression of Effete (Eff), a key E2 ubiquitin-conjugating enzyme during IMD signaling. Intriguingly, ectopic expression of eff effectively rescued the immune defects caused by loss of Cul2. Taken together, the results of our study underscore the critical role of Cul2 in ensuring robust IMD signaling activation, highlighting its importance in the innate immune defense against microbial infection in Drosophila.

Salidroside Derivative SHPL-49 Exerts Anti-Neuroinflammatory Effects by Modulating Excessive Autophagy in Microglia

The neuroinflammation triggered by cellular demise plays a pivotal role in ameliorating the injury associated with ischemic stroke, which represents a significant global burden of mortality and disability. The compound SHPL-49, a derivative of rhodioloside, was discovered by our research team and has previously demonstrated neuroprotective effects in rats with ischemic stroke. This study aimed to elucidate the underlying mechanisms of SHPL-49's protective effects. Preliminary investigations revealed that SHPL-49 effectively alleviates PMCAO-induced neuroinflammation. Further studies indicated that SHPL-49 downregulates the expression of the lysosomal protein LAMP-2 and reduces lysosomal activity, impeding the fusion of lysosomes and autophagosomes, thus inhibiting excessive autophagy and increasing the expression levels of the autophagy proteins LC3-II and P62. Furthermore, SHPL-49 effectively reverses the NF-κB nuclear translocation induced by the autophagy inducer rapamycin, significantly lowering the expression levels of the inflammatory factors IL-6, IL-1β, and iNOS. In a co-culture system of BV2 and PC12 cells, SHPL-49 enhanced PC12 cell viability by inhibiting excessive autophagy in BV2 cells and reducing the ratio of apoptotic proteins Bax and BCL-2. The overall findings suggest that SHPL-49 exerts its neuroprotective effects through the inhibition of excessive autophagy and the suppression of the NF-κB signaling pathway in microglia, thereby attenuating neuroinflammation.

Toll-mediated airway homeostasis is essential for fly survival upon injection of RasV12-GFP oncogenic cells

Toll signaling is well known for its pivotal role in the host response against the invasion of external pathogens. Here, we investigate the potential involvement of Toll signaling in the intersection between the host and oncogenic cells. We show that loss of myeloid differentiation factor 88 (Myd88) leads to drastic fly death after the injection of RasV12-GFP oncogenic cells. Transcriptomic analyses show that challenging flies with oncogenic cells or bacteria leads to distinct inductions of Myd88-dependent genes. We note that downregulation of Myd88 in the tracheal system accounts for fly mortality, and ectopic tracheal complementation of Myd88 rescues the survival defect in Myd88 loss-of-function mutants following RasV12-GFP injection. Further, molecular and genetic evidence indicate that Toll signaling modulates fly resistance to RasV12-GFP cells through mediating airway function in a rolled-dependent manner. Collectively, our data indicate a critical role of Toll signaling in tracheal homeostasis and host survival after the injection of oncogenic cells.

Identification and functional analysis of CG3526 in spermatogenesis of Drosophila melanogaster

Spermatogenesis is a critical part of reproduction in insects; however, its molecular mechanism is still largely unknown. In this study, we identified a testis-specific gene CG3526 in Drosophila melanogaster. Bioinformatics analysis showed that CG3526 contains a zinc binding domain and 2 C2 H2 type zinc fingers, and it is clustered to the vertebrate really interesting new gene (RING) family E3 ubiquitin-protein ligases. When CG3526 was knocked down by RNA interference (RNAi), the testis became much smaller in size, and the apical tip exhibited a sharp and thin end instead of the blunt and round shape in the control testis. More importantly, compared to the control flies, only a few mature sperm were present in the seminal vesicle of C587-Gal4 > CG3526 RNAi flies. Immunofluorescence staining of the testis from CG3526 RNAi flies showed that the homeostasis of testis stem cell niche was disrupted, cell distribution in the apical tip was scattered, and the process of spermatogenesis was not completed. Furthermore, we found that the phenotype of CG3526 RNAi flies' testis was similar to that of testis of Stat92E RNAi flies, the expression level of CG3526 was significantly downregulated in the Stat92EF06346 mutant flies, and the promoter activity of CG3526 was upregulated by STAT92E. Taken together, our results indicated that CG3526 is a downstream effector gene in the JAK-STAT signaling pathway that plays a key role in the spermatogenesis of Drosophila.

Cumulus Cell Transcriptome after Cumulus-Oocyte Complex Exposure to Nanomolar Cadmium in an In Vitro Animal Model of Prepubertal and Adult Age

Cadmium (Cd), a highly toxic pollutant, impairs oocyte fertilization, through oxidative damage on cumulus cells (CCs). This study analysed the transcriptomic profile of CCs of cumulus-oocyte complexes (COCs) from adult and prepubertal sheep, exposed to Cd nanomolar concentration during in vitro maturation. In both age-groups, CCs of matured oocytes underwent RNA-seq, data analysis and validation. Differentially expressed genes (DEGs) were identified in adult (n = 99 DEGs) and prepubertal (n = 18 DEGs) CCs upon Cd exposure. Transcriptomes of adult CCs clustered separately between Cd-exposed and control samples, whereas prepubertal ones did not as observed by Principal Component Analysis. The transcriptomic signature of Cd-induced CC toxicity was identified by gene annotation and literature search. Genes associated with previous studies on ovarian functions and/or Cd effects were confirmed and new genes were identified, thus implementing the knowledge on their involvement in such processes. Enrichment and validation analysis showed that, in adult CCs, Cd acted as endocrine disruptor on DEGs involved in hormone biosynthesis, cumulus expansion, regulation of cell signalling, growth and differentiation and oocyte maturation, whereas in prepubertal CCs, Cd affected DEGs involved in CC development and viability and CC-oocyte communications. In conclusion, these DEGs could be used as valuable non-invasive biomarkers for oocyte competence.