Cell insight最新文献

The ATR-Chk1 pathway is essential in cellular responses to DNA damage and replication stress, whereas the role of long noncoding RNAs (lncRNAs) in regulating this pathway remains largely unknown. In this study, we identify an ATR and Chk1 interacting lncRNA (ACIL, also known as LRRC75A-AS1 or SNHG29), which promotes the phosphorylation of Chk1 by ATR upon DNA damages. High ACIL levels are associated with chemoresistance to DNA damaging agents and poor outcome of breast cancer patients. ACIL knockdown sensitizes breast cancer cells to DNA damaging drugs in vitro and in vivo. ACIL protects cancer cells against DNA damages by inducing cell cycle arrest, stabilizing replication forks and inhibiting unscheduled origin firing, thereby guarding against replication catastrophe and contributing to DNA damage repair. These findings demonstrate a lncRNA-dependent mechanism of activating the ATR-Chk1 pathway and highlight the potential of utilizing ACIL as a predictive biomarker for chemotherapy sensitivity, as well as targeting ACIL to reverse chemoresistance in breast cancer.

Organ development, regeneration and cancer initiation are typically influenced by the proliferation and lineage plasticity of tissue-specific stem cells. Prostate intermediate cells, which exhibit characteristics of both basal and luminal cells, are prevalent in pathological states and during organ development. However, the identity, fate and function of these intermediate cells in prostate development are not well understood. Through single-cell RNA-seq analysis on neonatal urogenital sinus tissue, we identified intermediate cells exhibiting stem cell potential. A notable decline in the population of intermediate cells was observed during prostate development. Prostate intermediate cells were specifically labeled in early and late postnatal development by the enhanced dual-recombinase-mediated genetic tracing systems. Our findings revealed that these cells possess significant stem cell capabilities as demonstrated in organoid formation and cell fate mapping assays. These intermediate cells also exhibited intrinsic bipotential properties, enabling them to differentiate into both basal and luminal cells. Additionally, we discovered a novel transition from intermediate cell expressing neuroendocrine markers to neuroendocrine cell during prostate development. This study highlights intermediate cells as a crucial stem cell population and enhances our understanding of their role in prostate development and the plasticity of prostate cancer lineage.

Nipah Virus (NiV) and Hendra Virus (HeV), are the prototype species of the genus Henipavirus and are highly pathogenic agents capable of causing fatal diseases in both animals and humans. Both NiV and HeV are classified as biosafety level-4 (BSL-4) restricted pathogens and remain the only henipaviruses within the genus known to cause systemic, severe respiratory and encephalitic henipaviral disease, and represent substantial transboundary threats. There are no approved prophylactic or therapeutic treatments for human henipavirus infections, and the World Health Organization acknowledges them as priority pathogens needing urgent research. The discovery of Cedar virus (CedV), the only recognized non-pathogenic henipavirus, has provided a number of unique opportunities to study henipavirus and host interactions and also facilitate countermeasure development research at lower BSL-2 containment. This review will highlight the unique aspects of CedV biology and how it has been exploited as a model for developing therapeutic strategies against more virulent henipavirus species.

Cell fate determination is an intricate process which is orchestrated by multiple regulatory layers including signal pathways, transcriptional factors, epigenetic modifications, and metabolic rewiring. Among the sophisticated epigenetic modulations, the repressive mark H3K27me3, deposited by PRC2 (polycomb repressive complex 2) and removed by demethylase KDM6, plays a pivotal role in mediating the cellular identity transition through its dynamic and precise alterations. Herein, we overview and discuss how H3K27me3 and its modifiers regulate pluripotency maintenance and early lineage differentiation. We primarily highlight the following four aspects: 1) the two subcomplexes PRC2.1 and PRC2.2 and the distribution of genomic H3K27 methylation; 2) PRC2 as a critical regulator in pluripotency maintenance and exit; 3) the emerging role of the eraser KDM6 in early differentiation; 4) newly identified additional factors influencing H3K27me3. We present a comprehensive insight into the molecular principles of the dynamic regulation of H3K27me3, as well as how this epigenetic mark participates in pluripotent stem cell-centered cell fate determination.

Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related deaths worldwide and presents a significant threat to human health. Despite its prevalence, the underlying regulatory mechanisms of HCC remain unclear. In this study, we integrated RNA-seq datasets, proteome dataset and survival analysis and unveiled Stratifin (SFN) as a potential prognostic biomarker for HCC. SFN knockdown inhibited HCC progression in cell cultures and mouse models. Conversely, ectopic expression of Sfn in primary mouse HCC model accelerated HCC progression. Mechanistically, SFN acted as an adaptor protein, activating AKT1 signaling by fostering the interaction between PDK1 and AKT1, with the R56 and R129 sites on SFN proving to be crucial for this binding. In the syngeneic implantation model, the R56A/R129A mutant of SFN inhibited Akt signaling activation and impeded HCC growth. Additionally, peptide inhibitors designed based on the binding motif of AKT1 to SFN significantly inhibited HCC progression. In summary, our findings establish that SFN promotes HCC progression by activating AKT signaling through the R56 and R129 binding sites. This discovery opens new avenues for a promising therapeutic strategy for the treatment of HCC.

R-loop, a chromatin structure containing one RNA:DNA hybrid and one unpaired single-stranded DNA, plays multiple biological roles. However, due to technical limitations, the landscapes and potential functions of R-loops during embryogenesis remain elusive. Here, we developed a quantitative and high-resolution ultra-low input R-loop profiling method, named ULI-ssDRIP-seq, which can map global R-loops with as few as 1000 cells. By using ULI-ssDRIP-seq, we reveal the R-loop dynamics in the zebrafish from gametes to early embryos. In oocytes, the R-loop level is relatively low in most regions of the nuclear genome, except maternal-inherited rDNA and mitochondrial genome. The correlation between R-loop and CG methylation dynamics during early development is relatively weak. Furthermore, either up- or down-regulation of global R-loops by knockdown or overexpression of RNase H1 causes a delay of embryonic development with dramatic expression changes in zygotic and maternal genes. This study provides comprehensive R-loop landscapes during early vertebrate embryogenesis and demonstrates the implication of R-loops in embryonic development.

The RNA-binding protein LUC7L3 is the human homolog of yeast U1 small nuclear RNA (snRNA)-related splicing factor Luc7p. While the primary function of LUC7L3 as an RNA-binding protein is believed to be involved in RNA metabolism, particularly in the splicing process, its exact role and other functions are still not fully understood. In this study, we aimed to elucidate the role of LUC7L3 and its impact on cell proliferation. Our study revealed that LUC7L3 depletion impairs cell proliferation compared to the other Luc7p paralogs, resulting in cell apoptosis and senescence. We explored the underlying mechanisms and found that LUC7L3 depletion leads to R-loop accumulation, DNA replication stress, and genome instability. Furthermore, we discovered that LUC7L3 depletion caused abnormalities in spindle assembly, leading to the formation of multinuclear cells. This was attributed to the dysregulation of protein translation of spindle-associated proteins. Additionally, we investigated the interplay between LUC7L3 and SRSF1 and identified SRSF1 as an upper stream regulator of LUC7L3, promoting the translation of LUC7L3 protein. These findings highlight the importance of LUC7L3 in maintaining genome stability and its relationship with SRSF1 in this regulatory pathway.